I'd still dose some macros atleast once a week even after the plants have settled in. U can stop the excel dosing after a month if u wish, Just means u will get slower growth. The extra co2 is good to get them established tho and the glut in excel helps keep initial algae blooms away.
Try to get an organic top soil with no added fertilisers. U want one that has abit of peat mixed in with it aswell. A lot of people use miracle grow organic top soil. I used Osmacote seed raising mix.
You can also add a layer of red clay between the soil to give abit of extra iron. U want red modelling clay or clay powder. Steer clear of polymer clay. Organic is best.
Best way to put it in the aquarium in tip it in and rack it back an inch from the front and side glass (just so the gravel fits between the glass and soil) as it looks a lot neater.
Once you've got the soil in and the gravel cap over the top put a plastic bag over the gravel and slowly fill the tank (pouring the water on the plastic bag to stop any stiring of the substrate. Fill the tank completely and then drain it to the substrate level. Do this 4 times over.
Don't add any fish untill your ammonia levels reach 0. Plant as heavy as u can. It's best to fully plant your scape at the start rather than planting over a few weeks.
Dose ferts from day one aswell as excel.
This should help